IMHS clinical experience in the treatment of peritrochanteric fractures. The results of a multicentric Italian study of 981 cases.

This retrospective study evaluates the results obtained in five Italian departments of traumatology in the treatment of peritrochanteric (pertrochanteric and subtrochanteric) fractures by the intramedullary hip screw (IMHS; Smith & Nephew Richards, Memphis, TN, USA) nail. One thousand two hundred and seventy-three patients were treated with the IMHS nail between March 1992 and February 2000. The results of these operations were evaluated clinically and radiological in 981 patients. The 90.3% of patients could walk unaided or with simple support. Because of the low complication rate requiring re-operation (postoperative shaft fractures, screw penetrated the acetabulum, cut out and non-union) (1.7%), we think that this device is an advance in the treatment of peritrochanteric fractures.

Articular cartilage repair in rabbits by using suspensions of allogenic chondrocytes in alginate.

The feasibility of allogenic implants of chondrocytes in alginate gels was tested for the reconstruction in vivo of artificially full-thickness-damaged articular rabbit cartilage. The suspensions of chondrocytes in alginate were gelled by the addition of calcium chloride solution directly into the defects giving in situ a construct perfectly inserted and adherent to the subchondral bone and to the walls of intact cartilage. The tissue repair was controlled at 1, 2, 4 and 6 months after the implant by NMR microscopy, synchrotron radiation induced X-ray emission to map the sulfur of glycosaminoglycans and by histochemistry. Practically a complete repair of the defect was observed 4-6 months from the implant of the chondrocytes with the recovery of a normal tissue structure. Controls in which Ca-alginate alone was implanted developed only a fibrous cartilage.

Zinc mapping in bone tissues by histochemistry and synchrotron radiation-induced X-ray emission: correlation with the distribution of alkaline phosphatase.

Zinc distribution in osteons was mapped by synchrotron radiation-induced X-ray emission analysis in both human and porcine adult bone, as well as in porcine bone by histochemistry using Timm's method. Both procedures showed that zinc is not uniformly distributed, being in its highest concentration on haversian bone surfaces. When Timm's method was applied in conjunction with a procedure leading to partial zinc extraction, three zinc pools were specifically detected: a loose one, found in the mineralizable osteoid; a mineral one, bound to the bone mineral; and a tenacious one, firmly bound to an organic component located in the osteoid and mineralizing organic matrix. The alkaline phosphatase distribution was also mapped in porcine adult bone by histochemistry and immunohistochemistry and it was found codistributed with tenacious zinc mainly at the calcification front. The data suggest that alkaline phosphatase is buried as a bone matrix protein during initial mineralization.

Magnetic resonance imaging of articular cartilage: ex vivo study on normal cartilage correlated with magnetic resonance microscopy.

The aims of this study were (a) to compare the MR appearance of normal articular cartilage in ex vivo MR imaging (MRI) and MR microscopy (MRM) images of disarticulated human femoral heads, (b) to evaluate by MRM the topographic variations in articular cartilage of disarticulated human femoral heads, and subsequently, (c) to compare MRM images with histology. Ten disarticulated femoral heads were examined. Magnetic resonance images were obtained using spin-echo (SE) and gradient-echo (GE) sequences. Microimages were acquired on cartilage-bone cylindrical plugs excised from four regions (superior, inferior, anterior, posterior) of one femoral head, using a modified SE sequence. Both MRI and MRM images were obtained before and after a 90 degrees rotation of the specimen, around the axis perpendicular to the examined cartilage surface. Finally, MRM images were correlated with histology. A trilaminar appearance of articular cartilage was observed with MRI and with a greater detail with MRM. A good correlation between MRI and MRM features was demonstrated. Both MRI and MRM showed a loss of the trilaminar cartilage appearance after specimen rotation, with greater evidence on MRM images. Cartilage excised from the four regions of the femoral head showed a different thickness, being thickest in the samples excised from the superior site. The MRM technique confirms the trilaminar MRI appearance of human articular cartilage, showing good correlation with histology. The loss of the trilaminar appearance of articular cartilage induced by specimen rotation suggests that this feature is partially related to the collagen-fiber orientation within the different layers. The MRM technique also shows topographic variations in thickness of human articular cartilage.

[Magnetic resonance of the cartilages of the large joints]. / Risonanza magnetica della cartilagine delle grandi articolazioni.

MRI of the articular cartilage requires a careful technical approach since this structure is very thin, with a peculiar internal architecture between the supporting matrix and the cell component. On MR images the normal articular cartilage has a zonal appearance. To optimize the variables for best visualization of the internal architecture of the hyaline articular cartilage, an ex vivo and in vivo study was carried out. Accurate T1 and T2 relaxation times of the articular cartilage were obtained with a particular mixed sequence and then used to create isocontrast intensity graphs. The latter allowed, in all pulse sequences (SE and GRE), the best combination of TR, TE and FA to optimize signal differences between cartilage areas. A trilaminar pattern was demonstrated, with a superficial and a deep hypointense areas, in all sequences, together with an intermediate area which was moderately hyperintense on SE images and markedly hyperintense on GRE images. In the current literature, MRI appears to have been widely used to investigate hyaline cartilage conditions. In many series, the technique proved its efficacy in assessing both acute (traumatic cartilage fractures, osteochondritis dissecans, arthritis) and chronic (arthrosis, chondromalacia patellae, Hoffa's disease, synovial plica syndrome) conditions of the articular cartilage. T2-weighted sequences (both SE and GRE) are widely known as the most accurate in assessing cartilage conditions, which depends mainly on the arthrographic effect of synovial fluid on T2-weighted images. Of late, also MR arthrography, especially MR arthrography after the i.v. administration of Gadolinium, has emerged as an outstanding technique to investigate articular cartilage conditions. On the basis of MR arthrography findings, some authors suggested a classification of osteochondritis dissecans, arthrosis and chondromalacia patellae on MR images. MR stages seem to be closely correlated with the histologic classification suggested for these conditions.

Three-dimensional computed tomography of the acetabulum.

Acetabular fractures represent a complex variety that are classified in different types. Conventional radiology is often inadequate to demonstrate and classify the fractures. Computed tomography (CT) has already been shown to be superior in this field. A further advantage of CT is represented by the recent availability of three-dimensional (3D) images that are realized from axial CT scans by means of a new software. The Authors report the applications of this new software to the study of the normal acetabulum and in patients with fractures. 3D images allows an effective demonstration of the fracture, its irradiation and the dislocation of bone fragments. The information is contained in one or few images rather than many axial images. Therefore the role of 3D images may be considered complementary to axial CT scans.